The question is repeatedly asked whether an oncogenic virus can be transmitted from animal to man or man-to-man. The most likely place for such an exchange would be in the laboratory where proximity to the potentially transmissible agent is closest. No evidence for this belief has accumulated to date. Before undue alarm is aroused in exposed populations and more extensive protective mechanisms are required in laboratories, epidemiological studies are needed to determine whether there is any current evidence of a risk. At the present time we are conducting case-control studies of all cancer deaths and of cancers at specific sites to determine whether there is an association of these cancer deaths with exposure to all viruses or specific classes of viruses. A prospective study of scientists who are occupationally exposed to viruses as well as other agents is currently in progress. If a risk is noted in these exposed groups, the finding would lend support to the theory that viruses could cause some human cancers. BIBLIOGRAPHIC REFERENCES: Matanoski GM, Henderson MM, Stine OC, Courpas C, Hepner R., Walker S: The effectiveness of phonocardioscan screening for theo detection of heart disease in school-age children. Accepted for publication Amer. J. Public Health 67, 1977 (in press). Matanoski GM, Landau E, Elliott E: Progress in a Community Arsenic Study. Submitted to Symposium of Toxic Substances in Air & Environment, Air Pollution Control Association. Accepted for publication March 1977. (in press)